var temp = “This is a string.”;<br /> var count = (temp.match(/is/g) || []).length;<br /> console.log(count);</p> <p>Output: 2</p> <p>Explaination : The g in the regular expression (short for global) says to search the whole string rather than just find the first occurrence. This matches ‘is’ twice.

function count(str, find) {<br /> return (str.split(find)).length – 1;<br /> }</p> <p>count(“Good”, “o”); // 2

function countOccurences(string, word) {<br /> return string.split(word).length – 1;<br /> }<br /> var text=”We went down to the stall, then down to the river.”;<br /> var count=countOccurences(text,”down”); // 2

// String Prototype: myCount = myString.polycount(“countThis”)<br /> String.prototype.polycount = function (criteria) {<br /> return this.split(criteria).length – 1 }<br /> // Arrow Function (STR): myCount = strCount(myString, “countThis”)<br /> const strCount = (stack, find) => stack.split(find).length – 1<br /> // Array Prototype: myCount = myArray.polycount(“countThis”)<br /> Array.prototype.polycount = function (criteria) {<br /> return this.join(“”).split(criteria).length – 1 }<br /> // Arrow Function (ARR): myCount = arrCount(myArray, “countThis”)<br /> const arrCount = (stack, find) => stack.join(“”).split(find).length – 1

kamlesh is good boy and good programmer

function countInstancesOf(letter, sentence) {<br /> var count = 0;</p> <p> for (var i = 0; i < sentence.length; i++) {<br /> if (sentence.charAt(i) === letter) {<br /> count += 1;<br /> }<br /> }<br /> return count;<br /> }

gg99999

// No Regex Version (With Overlapping)<br /> // str => input string<br /> // sub => input substring<br /> // returns number of occurrences of sub in str with overlaping</p> <p>const countOccurrences = (str, sub) => {<br /> let count = 0;<br /> pos = str.indexOf(sub);</p> <p> while(pos>=0){<br /> count++;<br /> pos++;<br /> pos = str.indexOf(sub, pos)<br /> }<br /> return count;<br /> }